Tetraethylenepentamine-Modified Silica Nanotubes for Low-Temperature CO₂ Capture

The objective of this research is to develop a new type of CO 2 sorbent. The sorbents were synthesized with mesoporous ethane–silica nanotubes (E–SNTs) and tetraethylenepentamine (TEPA). They were characterized by nitrogen adsorption/desorption, thermogravimetric analysis, and infrared spectroscopy. A fixed-bed reactor equipped with an online mass spectrometer was used to test the CO 2 capture performances of the sorbents. It was found that 75 °C is the optimal CO 2 adsorption temperature for amine-impregnated E–SNT sorbents. The highest CO 2 sorption capacities achieved with E–SNTs with 50 wt % TEPA loading (E–SNTs–50%) without and with uses of water vapor are 3.58 and 4.74 mmol/g, respectively, under the conditions of a 10.0% CO 2 /N 2 mixture at 75 °C. Cyclic CO 2 adsorption–desorption test results indicate that the new composite sorbents are stable and regenerable.